Note 3 - Significant Accounting Policies - Estimated Useful Lives of Assets (Details)	3 Months Ended
	Mar. 31, 2017
Building and Building Improvements [Member] | Minimum [Member]
Estimated useful life (Year)	10 years
Building and Building Improvements [Member] | Maximum [Member]
Estimated useful life (Year)	44 years
Tenant Improvements [Member]
Estimated useful life	Shorter of useful life or lease term
Furniture, Fixtures and Equipment [Member] | Minimum [Member]
Estimated useful life (Year)	3 years
Furniture, Fixtures and Equipment [Member] | Maximum [Member]
Estimated useful life (Year)	15 years